Secret Clearance
Secret is applied to information that reasonably could be expected to cause serious damage to the national security if disclosed to unauthorized sources.

This level is reinvestigated every 10 years.

Confidential Clearance
Confidential is applied to information that reasonably could be expected to cause damage to the national security if disclosed to unauthorized sources. The vast majority of military personnel are given this very basic level of clearance.

This level needs to be reinvestigated every 15 years.

Clearance Reinvestigation
Reinvestigations are more important than the original investigation because those individuals who have held clearances longer are more likely to be working with increasingly critical information.